The objectives of this project are to identify and describe environmental and host determinants of cancer in areas at high risk of cancer through the use of analytical epidemiologic and biometric techniques, particularly case-control studies of specific cancers. A case-control study of renal cancer was initiated during the year in Minnesota, which leads the nation in rates of this malignancy. The study will evaluate the role of diuretics, widely-prescribed medications recently linked to renal tumors in experimental animals. Data analyses from a large multi-center study of oral cancer revealed protective effects for diets high in fresh fruit and vegetable intake among both blacks and whites, but lower levels of consumption may contribute to the higher rates of this tumor among blacks. In studies in high-risk areas overseas, vitamin C and E intake was associated with reduced risk of stomach cancer in Italy. Consumption of the vitamins helps account for the markedly lower risk of this cancer in southern provinces. In China, air pollution from home heating and cooking was found to contribute to the elevated rates of lung cancer in Shenyang, but no effect of indoor radon was detected. Vitamin/mineral intervention trials continued in Linxian, a rural Chinese county with the world's highest rate of esophageal cancer, while an investigation of the determinants of gastric precancerous lesions and their rates of transition to stomach cancer was launched in Shandong Province.